The present invention relates to an electrode active material for a secondary lithium battery and a secondary lithium battery having a positive or negative electrode prepared from the electrode active material. Specifically, the present invention is characterized in that is it possible to provide a lithium secondary battery having a light weight and high energy density.
A lithium secondary battery that utilizes oxidation and reduction of lithium has been used as a new type of battery having high capacity and high energy density.
As a positive electrode material for a positive electrode of a lithium secondary battery, an oxide of a transition metal, for example, manganese, cobalt, nickel, iron, vanadium and niobium and the like, and a lithium transition metal oxide where lithium is included in the transition metal oxide, have been used.
However, when the above described material is used for the positive electrode of a lithium secondary battery, the battery is heavy and is increased in cost. It is also a problem that capacity per weight is not always sufficient, and a lithium secondary battery that is light in weight and has high energy density cannot be obtained.
It has been tried to use sulfur as an electrode material of a secondary battery in the past. Sulfur requires high temperature for a charge discharge reaction. Therefore, it is difficult to use it for a general secondary battery.
The use of an organic sulfide compound, for example, 2,5-dimercapto-1,3,4-thiadiazole (DMcT) or the like as a positive electrode material has recently been studied.
However, there is a problem that the organic sulfide compound includes many elements, for example, C, H, and the like, that do not participate in a charge discharge reaction, and capacity per unit weight is reduced compared to sulfur alone.
An object of the present invention is to solve the problems explained above. That is, an electrode material for a lithium secondary battery is improved so as to obtain a lithium secondary battery that is light in weight and has high energy density.
The present invention provides an electrode material that includes sulfur and a catalyst material that reduces activation energy of an addition reaction when lithium reacts with sulfur at a temperature not greater than 60xc2x0 C. to solve problems described above.